i think i did spot a cold solder joint on the IDE header, what do u suggest if i see that?

The suggestions for what to do in that situation are detailed in that FAQ entry. Please refer to it for instructions.

and should i just buy a cable at the computer store to be safe?

The cables are custom-made and can't be bought off-the-shelf. The best way to get replacements is what's suggested in that FAQ entry: ordering one from support. If you tried to buy parts off-the-shelf to replace it, you'd have to crimp your own connectors, therefore taking a risk that your replacement cable might be worse than the original one.

If there really is a visible problem with the IDE header, I wouldn't worry about the cable, it would be the IDE header almost certainly. Does it look exactly like that photo, where the end pins lift up from the pad when you wiggle the header?