If you want to go back to the original Dragon Age today, you'll need some help. Origins was made in the Eclipse engine, which had some long-standing bugs that never got patched and given there are "maybe 20 people left at BioWare" who understand how it works, aren't likely to ever be officially fixed. Unofficially, they've already been solved and all it takes is a dive into the PC Gaming wiki and Nexus Mods to sort them out.
Without these patches, running Dragon Age: Origins is likely to make your PC overheat...