Hello, Need some help in determining a recent problem I've been having with my 500MHz Ti Powerbook. It has been acting very temperamental during startup where it will not startup at all, the fan will come on but no screen, or it will chime twice (and it's a weird sounding chime) and not startup, or it will freeze after logging in or during the log in stage. I got it to boot up once, but since then... it's dead. It will not startup. A friend tells me it's the internal lithium (PRAM?) battery that needs to be replaced... agree, disagree?? Any help would be appreciated! Thanks.