[Ann Bens]

Make file sequence size, see if that helps.

[Ann Bens]

Try a re-install, see if that helps.

[Ann Bens]

If you want to take advantage of MPE hardware you need a Nvidia graphicscard.
https://www.adobe.com/products/premiere/tech-specs.html

[Ann Bens]

Download CS5.5 that will give you full use of the program. No codec restrictions anymore.
https://www.adobe.com/cfusion/tdrc/index.cfm?product=premiere_pro

[Ann Bens]

There is no bug in the software.
Using a external HDD can cause problems. Move the files to an internal drive and try again.
A pc can go off after sometime even if its only used for video-editing. So ones in a while when things do not run very well a clean install is in order.

[Ann Bens]

When was the last time you did a clean install?

[Ann Bens]

Can you export it to a Lagarith avi.
That is what i do.

[Ann Bens]

Its better to downscale than to upscale.
I would stick to dvd. BD will never look good with the SD footage.
You could try this but its only for AE.
https://www.redgiantsoftware.com/products/all/magic-bullet-instant-hd/

[Ann Bens]

I second this.

[Ann Bens]

All programm incl. OS should be installed on the C;drive.