Hello all: My 4.5 year old Toshiba Satellite 1905-S301 laptop operates well for 30-45 minutes, then shuts off completely without warning. It can be restarted easily, but the same thing consistently happens. The fan seems a bit noisier, but it seems to run as it should. Also the unit has good air circulation around it and does not seem overly warm. Is this a hint that the hard drive is about to fail? Is it something else that can be repaired? Any chance this is related to updates from either Bit Defender or Microsoft? Both are done as offered. Also, it seems to have difficulty accessing links that appear in e-mails -- nothing happens when I click. I've backed up to an external hard drive recently, so except for additions to e-mail folders, most of my data can be transferred to a new drive if necessary. Current specs: Intel Pentium 4 processor, 2.0 GHz. 40GB hard drive. Windows XP with Service Pack 2. All assistance/advice welcome. Many thanks.