I do a lot of laptop upgrading, I would consider my self quite knowadgbale about this. To answer your question mostly likely yes, depending on what CPU you have already. here is a video I found on youtube
this is remarkably simple compared to my expirence with newer HP's. It look likes any Pentium 4 mobile cpu that is socket 478 would work. But you won't beable to put any thing newer in it. Here is what I found on ebay.
But your video card is your limit most likely you have intergrated graphics and this means that you can't upgrade it. As for the USB video cards consider them more like display adapters, so you can dual monitor, for things like power point, not really for gaming. The data through put on USB 2 is something like 480 Mb/sec and your modern video card is measured in Gigabytes/sec so a usb video card is just not possible.
Hope that answers your questions.
I've got a Dell Inspiron 1150 labtop recently to upgrade. I was wondering if it is possible to find a decent graphics card or processor that is even compatible with this labtop. I've heard about external graphics cards but I was wondering if there was another way. If anyone has any suggestions it would be great to let me know.