Capacitor problems- are they defective? Can I replace it with a similar capacitor or does it have to be the same?

Hi, I have been having problems with a PC and all effects the system is experiencing hints the problem is in the capacitors. So I took the motherboard out and checked them visually and found many of them have a slight bulge to the top (instead of a slight depression). So below is a photo I took of them. I marked four of the capacitors with red x’s and three with green check marks, from what I see I would say the three with the check marks are good and the four with the red x are bad, would anyone agree? (I never heard of a bad capacitor prior to my research on this particular system I am trying to fix). So in other words I am just not sure if they are bulging enough to say they appear to be defective so I would like another opinion.


My next question is about replacement capacitors. For example the capacitor with the red x has the following written on it: 6.3V, 1800 uf, 105 C (temp), ATWB, 802A, and has a logo which reads TK.  The size is 8mm x 25mm. I found similar ones on ebay- the only difference is the manufacturer and the hight of the capacitors (the diameter is the same but the ones on ebay are slightly shorter, they are only 19mm tall). So would the ones I found on ebay be a good canadate? Or do I have to find the EXACT same brand? Here is the ebay listing I found:

http://www.ebay.com/itm/Rubycon-Electrolytic-Capacitor-1800uF-6-3V-105-C-10-pc-/280494288593?pt=LH_DefaultDomain_0&hash=item414ec32ed1