Minecraft has been crashing for the past few days roughly one minute or less after startup

Minecraft has been crashing for me for the past few days, here is the report that the crash window gives me, I hope you are able to work with the information provided.

[20:33:04] [Client thread/INFO]: Setting user: LastofTimeLords
[20:33:04] [Client thread/INFO]: (Session ID is token:c2dd5ddc7b304256a3641d6df2ecc975:0b0f624cd2ed41658d55d480860f5542)
[20:33:08] [Client thread/INFO]: LWJGL Version: 2.9.1
[20:33:08] [Client thread/INFO]: Reloading ResourceManager: Default
[20:33:11] [Sound Library Loader/INFO]: Starting up SoundSystem...
[20:33:11] [Thread-6/INFO]: Initializing LWJGL OpenAL
[20:33:11] [Thread-6/INFO]: (The LWJGL binding of OpenAL. For more information, see http://www.lwjgl.org)
[20:33:14] [Client thread/INFO]: Created: 512x512 textures-atlas
[20:33:16] [Thread-6/INFO]: OpenAL initialized.
[20:33:16] [Sound Library Loader/INFO]: Sound engine started
[20:33:27] [Client thread/ERROR]: Exception reading C:\Documents and Settings\D620\Application Data\.minecraft\saves\Gallifrey 1_8\level.dat
java.util.zip.ZipException: Not in GZIP format
at java.util.zip.GZIPInputStream.readHeader(Unknown Source) ~[?:1.7.0_71]
at java.util.zip.GZIPInputStream.<init>(Unknown Source) ~[?:1.7.0_71]
at java.util.zip.GZIPInputStream.<init>(Unknown Source) ~[?:1.7.0_71]
at fz.a(SourceFile:13) ~[1.8.1.jar:?]
at bql.c(SourceFile:62) [1.8.1.jar:?]
at bqh.b(SourceFile:52) [1.8.1.jar:?]
at bxf.f(SourceFile:87) [1.8.1.jar:?]
at bxf.b(SourceFile:59) [1.8.1.jar:?]
at bxe.a(SourceFile:368) [1.8.1.jar:?]
at bss.a(SourceFile:812) [1.8.1.jar:?]
at bxp.a(SourceFile:216) [1.8.1.jar:?]
at bxe.a(SourceFile:342) [1.8.1.jar:?]
at bxp.a(SourceFile:471) [1.8.1.jar:?]
at bxe.k(SourceFile:405) [1.8.1.jar:?]
at bxe.p(SourceFile:382) [1.8.1.jar:?]
at bss.r(SourceFile:1480) [1.8.1.jar:?]
at bss.at(SourceFile:880) [1.8.1.jar:?]
at bss.a(SourceFile:317) [1.8.1.jar:?]
at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.1.jar:?]
[20:33:27] [Client thread/ERROR]: Exception reading C:\Documents and Settings\D620\Application Data\.minecraft\saves\Gallifrey 1_8\level.dat_old
java.util.zip.ZipException: Not in GZIP format
at java.util.zip.GZIPInputStream.readHeader(Unknown Source) ~[?:1.7.0_71]
at java.util.zip.GZIPInputStream.<init>(Unknown Source) ~[?:1.7.0_71]
at java.util.zip.GZIPInputStream.<init>(Unknown Source) ~[?:1.7.0_71]
at fz.a(SourceFile:13) ~[1.8.1.jar:?]
at bql.c(SourceFile:73) [1.8.1.jar:?]
at bqh.b(SourceFile:52) [1.8.1.jar:?]
at bxf.f(SourceFile:87) [1.8.1.jar:?]
at bxf.b(SourceFile:59) [1.8.1.jar:?]
at bxe.a(SourceFile:368) [1.8.1.jar:?]
at bss.a(SourceFile:812) [1.8.1.jar:?]
at bxp.a(SourceFile:216) [1.8.1.jar:?]
at bxe.a(SourceFile:342) [1.8.1.jar:?]
at bxp.a(SourceFile:471) [1.8.1.jar:?]
at bxe.k(SourceFile:405) [1.8.1.jar:?]
at bxe.p(SourceFile:382) [1.8.1.jar:?]
at bss.r(SourceFile:1480) [1.8.1.jar:?]
at bss.at(SourceFile:880) [1.8.1.jar:?]
at bss.a(SourceFile:317) [1.8.1.jar:?]
at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.1.jar:?]
[20:33:29] [Server thread/INFO]: Starting integrated minecraft server version 1.8.1
[20:33:29] [Server thread/INFO]: Generating keypair
[20:33:30] [Server thread/INFO]: Preparing start region for level 0
[20:33:31] [Server thread/INFO]: Preparing spawn area: 17%
[20:33:32] [Server thread/INFO]: Preparing spawn area: 68%
[20:33:32] [Server thread/INFO]: Changing view distance to 2, from 10
[20:33:33] [Server thread/INFO]: LastofTimeLords[local:E:29045568] logged in with entity id 13 at (-312.48877448998195, 64.0, -181.92489575169898)
[20:33:33] [Server thread/INFO]: LastofTimeLords joined the game
[20:33:38] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 4406ms behind, skipping 88 tick(s)
#

1. A fatal error has been detected by the Java Runtime Environment:
   #

2. EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x30c23060, pid=9112, tid=8676
   #

3. JRE version: Java(TM) SE Runtime Environment (7.0_71-b14) (build 1.7.0_71-b14)

4. Java VM: Java HotSpot(TM) Client VM (24.71-b01 mixed mode windows-x86 )

5. Problematic frame:

6. C [iglicd32.dll+0x43060]
   #

7. Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
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8. An error report file with more information is saved as:

9. C:\Documents and Settings\D620\Application Data\.minecraft\hs_err_pid9112.log
   #

10. If you would like to submit a bug report, please visit:

11. http://bugreport.sun.com/bugreport/crash.jsp

12. The crash happened outside the Java Virtual Machine in native code.

13. See problematic frame for where to report the bug.
    #
    AL lib: (EE) alc_cleanup: 1 device not closed