it has worked... must have been something wrong with ovi suite, because when I went onto nokia site to download current version of ovi suite, it started downloading and then asked if I either wanted to repair current version of ovi suite on pc, or uninstall it. i chose repair.
Its strange because I only installed ovi suite on my pc arund 2-3 weeks ago. would have thought it was up to date and functioning correctly... anyway, to summerise-
-for me the "battery taking out" didn't work
-the taking out of the memory card didn't work.
-strangely connecting it to pc helped it stabilise enough so I could go into menus and attempt to retrieve my data. thankfully!
-the soft reset didn't work
-the hard reset did work. it made my c:drive go from 112kb free with "low memory" warnings to 68mb free, and back to being a fast phone. did wipe everything from my phone though, so make sure you have a backup!
Thanks to jApi NL for the advice!