You can go on Ebay & will find a Nec that will fit but the one i'm buying for my Solo like yours will have to have the lower r. corner cut away so it will clear the floppy drive. The one i'm getting is a dvd burner & would'nt have it any other way. Mine has a cd-rw/dvd rom drive w/ no faceplate in it now. Looks kinda funny w/out it but it works ok. The dvd burner is what you need. it reads & writes dvd's & cd's all on one.
I just bought one on Ebay for $99.00 plus $12.00 shipping & did see the Nec 9550 brand there but did'nt want to go through the hassel of modifying it. Gateway specs does not show a dvd burner there. Decided after spending so much time trying to find the right one to go ahead & spend the extra money for the right one. It has the cutout already there.
I found the right dvd drive & installed it but had problems getting the burner software to recognize the burner. Finally found some software that would. Did some tweeking & got my data backed up to it, YEH!!! Now if I could only get my backup accomplished on my Emachine desktop.