Sounds like the browser to me.
Use firefox then install the flash player for that.
http://www.mozilla.org/en-US/
Also do you clean your cache?
Maintaining your computer
1. Left click on C drive> properties/run windows disc cleaner
2. Download Ccleaner from here: http://www.filehippo.com/
3. Install Ccleaner and run the cleaner top left, then run the registry cleaner below it on the left. you don’t need to backup the registry
4. Left click on C drive> properties>Tools> check now/disc scanner or in the case of Vista it’s called something else > tick both boxes > start, Prompt the scanner to scan upon next reboot and REBOOT COMPUTER)
#(Prepare to wait up to an hour)#
5. After Disk scan/Disk check has finished run windows Disc Cleaner again, Ccleaner again and registry cleaner again.
6. Then you must do a DEFRAGMENTAION of C drive which is START>ALL PROGRAMS>ACCESSORIES>TOOLS>DEFRAGMENTATION
Additional options: Remove current anti-virus as well as any adware and spy wear.
Free Microsoft Essentials Anti-virus http://www.microsoft.com/security/pc-security/mse.aspx