Today I scanned my computer with Kaspersky virus removal tool and it found three Trojans which avast didn’t detect as trojans and avast has also given me a few false positives on trojans Is avast bad at detecting Trojans 
Can you help improving detection?
Can you send the detected files to virus (at) avast (dot) com for analysis?
Sure :),I will send the files next time Kaspersky deleted the Trojans and I won’t be able this time
i think avast has poor detection rates for trojans. that’s a fact.
No program is perfect
Kaspersky has a reputation for being better for trojans
AVG is adding antispyware features by merging EWIDO
Sunbelt Counterspy is adding Anti Virus
etc
however if you think you have trojans try Trojan Hunter and A-Squared
The usual quarantine- do not delete and check for false positives applies
and do post up all hits in the appropriate forum
did kaspersky post a log?
installed or on line scan?
did you try a “scan on boot” with Avast?
You think… and then it’s a fact 
Tests aren’t that bad in favor of avast.
When I scan my computer with avast I get the error message unable to unpack files is this normal or is my computer infected
A simple forum search for “unable to unpack” reveals many replies.
the following should answer your question:
http://forum.avast.com/index.php?topic=16493.msg272916#msg272916
By examining 1) the reason given by avast! for not being able to scan the files, 2) the location of the files, you can get an idea of what program they relate to. You may need to expand the column headings to see all the text.
Files that can’t be scanned are just that, not an indication they are suspicious/infected, just unable to be scanned.
packed files
when unpacked
will be then scanned by Avast
encrypted and packed files which cannot be easily unpacked are common
not to worry
are these files from a trustworthy source?