Virus in download, Widows did not detect

I had troubles with allowing Windows to unzip a zipped folder so I looked
quickly for a new utility for unzipping, I had troubles using the alpha zip
and 7-zip that are located on the drive that has XP.

So in haste after frustrating times trying to unzip a folder that is routine
because I use the software, I downloaded Ace zip. I scanned the download with
CA that is up-to-date and it detected 0 viruses.

Upon installation, CA detected 4 viruses and Windows Defender then kicked in
and found one offending file and required a restart. I complied.

When I went to uninstall the zip program, there were two newly created
programs, one was cowabunga and the second was a toolbar.

I uninstalled Cowabunga but later found a folder named Cowabunga after the
uninstall.

Seems to me that CA should have detected the viruses when I scanned.

Also have a couple more oddities in Vista, it seems the clock can not keep
time, I have to continually reset my pc clock...?

Also Vista seems to not know when files are not being accessed.

I had an html editor opened and did have one file opened and I could not
delete the folder that contained that file. I closed that file out and there
were not any files open in my editor but yet Windows still thought the folder
was being accessed. I closed the program altogether and then could finally
delete the folder. This is pretty much the same as how Windows sometimes
thinks that your cd or dvd drive is in use and will deny you access