I need Help. I cannot install avast antivirus on my lap top.

I cannot install avast antivirus. When I m installing avast it will run out a “Note Pad” then show it " The system cannot find the path specified". How??? ???
Before i Use avast antivirus, i used “bit defender” antivirus. when i m using bit defender, i scan my lap top. Bit defender show tat my lap top is virus detected. Names " .vbs “. i try to delete it, but cannot.
Then i watched here a lot ppl also infected by this kind of “vbs” virus. Then i do it myself, i download avast antivirus,malware fixes, Hijackthis and also Spybot - Search & Destroy.
1st, I uninstall bit defender. then install malware fixes scan it and remove all of it. Is fixed some of the virus already. follow by tat i install the Avast antivirus. But i cannot install it… Now when i open my task manager also cannot. It will open the " Note Pad” again… Omg~~
i m Blurring now… then Double click my " C " Drive it will show " Cannot find script file “C:\h4ck3v1l.vbs”… What so I do?? Anybody please Help me…Thanks A lot!!! PLease Help me~

Hitman Pro 3 - Second Opinion Malware Scanner
http://www.surfright.nl/en/hitmanpro

Check your computer for Malware with

Malwarebytes Antimalware http://filehippo.com/download_malwarebytes_anti_malware/
after install click UPDATE and run quick scan, click on REMOVE SELECTED to quarantine anything found

SUPERAntiSpyware http://filehippo.com/download_superantispyware/
Are cookies really spyware and are they dangerous?
http://www.superantispyware.com/supportfaqdisplay.html?faq=26

If anything is found come back and post the scan logs here

Thanks u for help…

I already tried to download and scan it already…
But the problem still here…
Still Cannot install avast.
my task manager also cannot open.
Double click my " C " Drive it will show " Cannot find script file “C:\h4ck3v1l.vbs”
post the scan logs means use malware to scan then show u back the logs?
sorry… i m noob in computer…

Malwarebytes’ Anti-Malware 1.44
Database version: 3858
Windows 5.1.2600 Service Pack 2
Internet Explorer 6.0.2900.2180

3/12/2010 3:38:16 PM
mbam-log-2010-03-12 (15-38-16).txt

Scan type: Quick Scan
Objects scanned: 113901
Time elapsed: 5 minute(s), 3 second(s)

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

Memory Processes Infected:
(No malicious items detected)

Memory Modules Infected:
(No malicious items detected)

Registry Keys Infected:
(No malicious items detected)

Registry Values Infected:
(No malicious items detected)

Registry Data Items Infected:
(No malicious items detected)

Folders Infected:
(No malicious items detected)

Files Infected:
(No malicious items detected)

Above is a good example of posting a scan log.

(It shows your Windows as out of date, needing SP3 and IE updating. This was possibly a reason you got infected.)

Try Hitman Pro. If anything is found, you will get free use of it for thirty days for removal etc.

@ asamasam

See:
Support for Windows XP with SP2 and Windows Vista Ends July 13, 2010
http://forum.avast.com/index.php?topic=56809.0

IE6 is very vulnerable to attack.