Can't fix computer -- viruses, corrupt system files

This would appear to be a problem with your system, not malware. ( The MBAM file that you attached was not the log from running it, by the way. )

You could try creating this disc, which will get you into the Recovery Environment where you can run a system repair. ( You will need to change the boot order in the bios to boot to the cd-rom first. ):

Vista and Win7 Recovery disc

Since you are not having any malware problems, it is time to do our final steps:

1. We recommend you keep SUPERAntiSpyware and Malwarebytes Anti-Malware for scanning/removal of malware. Unless you purchase them, they provide no real time protection. They do not use any significant amount of resources ( except a little disk space ) until you run a scan.We recommend them for doing backup scans when you suspect a malware infection.
2. If we had you use ComboFix, uninstall ComboFix (This uninstall will only work as written if you installed ComboFix on your Desktop like we requested.)
   
   • Click START then RUN and enter the below into the run box and then click OK. Note the quotes are required
   • "%userprofile%\Desktop\combofix" /uninstall
     
     • Notes: The space between the combofix" and the /uninstall, it must be there.
     • This will uninstall ComboFix and also reset hidden files and folders settings back to Windows defaults.
     
     
   
   
3. Go back to step 6 of the READ ME and renable your Disk Emulation software with Defogger if you had disabled it.
4. Any other miscellaneous tools we may have had you install or download can be uninstalled and deleted.
5. If we had you download any registry patches like fixme.reg or fixWLK.reg (or any others), you can delete these files now.
6. If running Vista, it is time to make sure you have reenabled UAC by double clicking on the C:\MGtools\enableUAC.reg file and allowing it to be added to the registry.
7. Go to add/remove programs and uninstall HijackThis.
8. Goto the C:\MGtools folder and find the MGclean.bat file. Double click on this file to run this cleanup program that will remove files and folders related to MGtools and some other items from our cleaning procedures.
9. If you are running Win 7, Vista, Windows XP or Windows ME, do the below:
   
   • Refer to the cleaning procedures pointed to by step 7 of the READ ME
     for your Window version and see the instructions to Disable System Restore which will flush your Restore Points.
   • Then reboot and Enable System Restore to create a new clean Restore Point.
   
   
10. After doing the above, you should work thru the below link:
    
    • How to Protect yourself from malware!
    
    

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It will give you options to run a System restore or a start up repair. You would need your OS CD to do a repair install, which would keep your files and data.

 

You would need your OS CD to do a repair install. You can either try to borrow one, of the same version, or call the manufacturer and demand a disc. They often will send you one for a very nominal fee.