I have AVP/KAV as my main AV scanner. I recently updated from AVP 3.5 to KAV 4.0 but was not very impressed by the new version. Despite a Pentium 4 and 512mB ram my laptop slowed considerably with the new KAV Personal, even after updating to the latest version on the Kaspersky website. In addition the on demand scan speed was considerably slower. Apparently these are general problems with KAV 4 and I know from several postings at wilders that it is now considered as bloatware. Since I have the new keyfile for the new version and would like to revert back to the faster, leaner AVP 3.5 can someone answer the following questions. First, is AVP 3.5 compatible with XP Pro(my operating system). Kaspersky have told me no but I have read some posts where the Swiss version of AVP 3.5 is supposed to be compatible. Secondly, is my new keyfile sent for KAV 4 also useable with the older AVP? Third, do other people find the new program a drain on their systems? If I cannot find some improvement I will use KAV solely as a backup on demand scanner and use another less resource hungry one as my main scanner(Dr Web?) . Finally as this is my first post to your site I would just like to thank wilders and all their moderators for all their excellent help and knowledge found here. Long may it continue.