Vista - Eplorer.exe and other duplicates

My system is running fine but in my c/windows folder I have 5 explorer.exe IE
explorer.exe, explorer.exe (1) explorer.exe (2) can I delete these extra
numbered explorer.exe's?. I also have the same thing with many files in
system 32 IE: actveds.dll up to four (1) (2) and so forth, actxprxy.dll,
adpack.dll just to name a few. all have the orginal then like explorer.exe
there is a (1) (2) etc for many of these dll's. may I delete all these extras
and keep the original. Thank You for any help.
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Robin J Halpin