Yes, all the files and folders in "C:\Windows\TEMP" can be safely deleted (hence the name "TEMP"). Generally, the only problem that could arise is if a program is currently using one or more of the files when you delete the contents of this folder - a program install in progress for example. This can be avoided by always remembering to reboot the computer immediately before emptying the folder. Programs that need to use files in the "C:\Windows\TEMP" folder will recreate them as necessary.

thanks JBravo  I had thought that I could delete all the files in that folder but wasn't sure.  Panowl