Presumably you have antivirus installed. It may be an over sensitive anti virus causing a security problem that is preventing flash from being utilised.

Temporarily disable your AV and try the flash sites.

Failing that the only other option is to follow the instructions here http://kb2.adobe.com/cps/494/cpsid_49419.html

I know you said previously you are worried about editing the registry but if you create a restore point first you will have the peace of mind that you can recall the restore point if it doesn't fix it.

To create a restore point go to Programs > Accesories > Sysytem Tools > System Restore