[can someone tell me when can i delete issues safely?]

guys how will i know if the issues after scanning is safe to delete?

 

i have these:

unused file extensions OISbmpfile, OISgiffile, OISemffile, OISjpegfile, OIStiffile, urn-content classes

 

mising shared DLL: windows/system32/pxwma.dll

 

open with application issues: system32/cmmgr32.exe,1, system32/cmmgr32.exe/settings"%1"

 

activex/com issue: inprocserver32/c:windows/system32/plugin.ocx, inprocserver32/c:windows/system32/macromed/flash/flash.ocx

 

application path issues: cmmgr32.exe-c:/windows/system32/cmmgr32.exe

 

i havent deleted them yet since i have no idea what the h3ll these are. any thread explaining each issue? thanks