Thanks for the help.
I have been asked for hardware specs, so:
256 Mb Ram
1.7 GHz Celeron Processer
20 Gb Remaining Storage
Terrible Video Card... (From 2000)
Makes me cry, I have to give it a kick to start sometimes...

I should be upgrading to a new computer this summer though.
I guess I forgot about Alibre, a member of our CAD team used to use it. Does the Express version have the modelling ability of Inventor (I don't really need all the flashy features, like rendering and dynamic simulation)? AutoCad is expensive too, and the free version has no 3D in my experience. I don't really know which Free programs to trust, but Alibre seems alright.