URGENT-Comp infected by malware & RECYCLER virus--please help

Although i'm a bit experienced comp user & have faced anti-virus problems earlier---i cannot solve this one
My computer got infected by RECYCLER virus and other etc virus, through pen drive. I have AVAST and earlier whenever i inserted in the pc it had deleted the virus from pen drive but this time it could not.

firstly i saw
<1> then whenever i opened the computer an error message "regsvr.exe not found" came on screen
<2> regedit was not functioning
<3> Avast was continuously showing that some or the other exe file in my D and E hard drive was infected--so i put these in the quarantine (note my main drive is C)

drawing from my previous experiences
<1> I ran Malwarebytes Anti-Malware--the log file is as under
---------------------------------------------------------------
Malwarebytes' Anti-Malware 1.39
Database version: 2421
Windows 5.1.2600 Service Pack 2

5/19/2010 10:54:13 PM
mbam-log-2010-05-19 (22-54-13).txt

Scan type: Quick Scan
Objects scanned: 98364
Time elapsed: 9 minute(s), 37 second(s)

Memory Processes Infected: 0
Memory Modules Infected: 0
Registry Keys Infected: 0
Registry Values Infected: 1
Registry Data Items Infected: 6
Folders Infected: 0
Files Infected: 2

Memory Processes Infected:
(No malicious items detected)

Memory Modules Infected:
(No malicious items detected)

Registry Keys Infected:
(No malicious items detected)

Registry Values Infected:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\msn messsenger (Backdoor.Bot) -> Quarantined

and deleted successfully.

Registry Data Items Infected:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\DisableRegistryTools

(Hijack.Regedit) -> Bad: (1) Good: (0) -> Quarantined and deleted successfully.
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\DisableTaskMgr

(Hijack.TaskManager) -> Bad: (1) Good: (0) -> Quarantined and deleted successfully.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell (Hijack.Shell) -> Bad:

(Explorer.exe regsvr.exe) Good: (Explorer.exe) -> Quarantined and deleted successfully.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\AntiVirusDisableNotify (Disabled.SecurityCenter) ->

Bad: (1) Good: (0) -> Quarantined and deleted successfully.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\FirewallDisableNotify (Disabled.SecurityCenter) ->

Bad: (1) Good: (0) -> Quarantined and deleted successfully.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\UpdatesDisableNotify (Disabled.SecurityCenter) -> Bad:

(1) Good: (0) -> Quarantined and deleted successfully.

Folders Infected:
(No malicious items detected)

Files Infected:
C:\WINDOWS\system32\regsvr.exe (Backdoor.Bot) -> Quarantined and deleted successfully.
C:\WINDOWS\regsvr.exe (Backdoor.Bot) -> Quarantined and deleted successfully.
--------------------------------------------------------
[DID I COMMIT A MISTAKE BY DELETING THESE FILES OR SHOULD I HAVE QUARANTINED THEM]

Now i am seeing
<1>regedit is running
<2>BUT many programs are non functional like firefox, chrome etc., jpg files, EXCEL
it is giving error "Windows cannot access the specified path or file. You may not have the appropriate permission to access"

By the way I aslo ran spyware doctor--it gave a list but could not remove them as it is A FREE VERSION
The list is worm.autoit(6), worm.sality(24), trojan.generic(1) , keylogger(1)

please help me--what should i do-- i have important data i need for my exams

Follow ALL of the instructions in the Sticky at the top of the Antivirus forum.

Really I found KasperSky anti virus best, I using it. you try this for resolve this problem as well. Hope you'll get solution.