Regsvr.exe not find.

Hello,
Hello,
i m having a problem of getting "WINDOWS CANNOT FIND REGSVR.EXE FILE,TRY TO SEARCH IN OTHER LOCATION" msg at start up of my computer window screen..how do i solve it?pls support me do solve this problem..and i hav another problem.i wanted to put kaspersky antivirur software to my pc,but i hav a problem that mcafee antivirus in older days,i want to remove it.but i cant delete it.it is also showing error report of "CANNOT DELETE FILE FROM THE SOURCE".before i delete mcafee i cant install kaspersky.tel me hw to solve my these two problems,as early as possible..pls