Unable to update or reinstall

Hello,

About 1-6 weeks ago, update of the program (not virus database) stopped working. The error was something like: Not enough rights to…

Today I reinstalled using remove tool for avast, and after that tried to reinstall. But reinstall was not successful. I disabled windows firewall, but no luck.

The install just says that error in install, nothing else.

I have windows xp with admin rights.

It would help if I would know what the next line is supposed to do.
The last lines in install log are:

Software\Avast5\Setup\vps_win32-19b.vpx
20.04.2010 21:30:55 file: Direct delete of file: C:\Program Files\Alwil Software\Avast5\Setup\winsys-3.vpx
20.04.2010 21:30:55 package: Transferred: files 0, bytes 0, time 3250 ms
20.04.2010 21:30:55 package: Retries: total 0, files 0, servers 1
20.04.2010 21:30:55 general: DldSrc set to inet
20.04.2010 21:30:56 general: Server definition(s) loaded for ‘main’: 334 (maintenance:0)
20.04.2010 21:30:56 general: SelectCurrent: selected server ‘Download836 AVAST5 Server’ from ‘main’
20.04.2010 21:30:56 internet: SYNCER: Type: use IE settings
20.04.2010 21:30:56 internet: SYNCER: Auth: another authentication, use WinInet
20.04.2010 21:31:00 internet: Sending stats ‘http://174.120.185.178/cgi-bin/iavs4stats.cgi’: 00000000 204
20.04.2010 21:31:00 file: NeedReboot=false
20.04.2010 21:31:00 general: Return code: 0x00000005 [Access is denied.]
20.04.2010 21:31:00 general: Stopped: 20.04.2010, 21:31:00

Update to the situation:

F-secure won’t install itself. It says:
F-Secure Management Agent 8.20:
No components left using this common component.

Virus- ja vakoilusuojaus 9.20:
Ascendancy component F-Secure System File Update cannot be installed etc…….

Virus of some kind? Any ideas what I should do next?