increase your windows swap file space, the 'virtual memory'.
close down unneeded applications to save on memory use. if you're working while also online to the internet, go offline so you can close down anti-virus, anti-spyware and all that stuff associated with internet protection.
go
http://www.blackviper.com and read up on freeing up resources in windows. windows runs a LOT of junk you just dont need and it all eats up computer resources. this guy knows more about windows JUNK than anyone else i know.
even though windows xp doesnt use very well ram in excess of 2 gigs, it will use it. so, increase your ram.
lower your screen resolution on windows. displaying in VERY large resolutions eats resources over and above smaller resolutions sizes and 'should' refresh faster. no guarantees, but it shld.
change your monitor's refresh rate to a lower setting. this may or may not gain you much, depending on vid card type and monitor type.
cut your file in half. i've worked on VERY large files before, 90 megs and larger. and where i dont recall one of those with 200 layers, i do know that i can often just do a copy merge and paste as new layer somewhere, save the file and then do a control c, control v on that copy merged layer and start 'fresh' on that 'new' image while killing the original out of memory. this can free up a TON of resources. only you will be able to determine if this is possible for your large, current file, however. but, hopefully you can do this.
and even if you dont break the file up, you can often just save the file, kill it and reload it. this will usually free up quite a bit of memory due to the undo-redo nature of graphic editors. all those undos have to be stored in memory so that photoshop knows what to undo. that eats up memory like mad. sometimes this is saved off to the scratch disk or swap file, but not always. so, save, kill and reload when Photoshop is slogging down to a crawl.
and, if you're working on this type of file often, upgrade your computer. get a quad-core at the fastest cpu speed you can find and afford. the quads really do make a BIG difference.
also, i've never known or worked on a large file where i couldnt just delete some of my early layers. again, this is your determination here, but i'd seriously take a look at that possibility. 1.7 gigs on load-up is pretty insane
