Do you have any toolbar or other helper application that blocks Flash? Some
toolbars that block pop-ups also have a Flash-blocker.
See this site for .reg file to make sure Flash is enabled in the registry: http://www.kellys-korner-xp.com/xp_tweaks.htm - line 363 on the left.
Download to your desktop and double-click to merge to your registry or right
click and choose Merge - or Edit to see exactly what modifications it will
make to your registry.
Check your security settings - Tools...Internet Options...Security tab,
click Internet Zone, click Custom, and make sure automatic downloads are
enabled. Ensure that "Download Signed ActiveX controls" and "Run ActiveX
controls and plug-ins" are not disabled.
If you are behind a proxy server or are in an administered network
environment - they may be blocking Flash.
Tools...Manage Add-ons...change menu to "Add-ons that have been used by IE"
and make sure that "Shockwave ActiveX Control" and "Shockwave Flash Object"
are set to "enabled".