In Nov 2013 I used v0.8.5 to buy a few BTC and learn the system. No problems. It did what it said on the tin.
After a crash in August 2014 I installed v0.9.2.1 (saving wallet.dat). It took a week to synchronise with the block chain. Thereafter it has refused to synchronise at all. Often it throws an exception, but if not it just seems to be inert.
I have 32 bit Windows XP Pro, an AMD triple core pentium running at 2.31 GHz and I have 1.75 Gb of RAM.
Is it obvious to you guys what's wrong ?
Can I help myself by using a "thin client" like Electrum bearing in mind that I don't understand what a thin client is ?
Although I only have a few hundred dollars in the wallet, it's making me a bit annoyed to lose control of it !
I see references in other posts to "having 10 connections to the bitcoin network". I don't know what this means. Should I know ? How do I find out how many... ?
Windows XP and 32 Bit system MIGHT be the cause of the reason. I have seen a lot of people having problems with windows XP. Bitcoin Core should use less than 1GB of ram based on my experiences. How much disk space do you have?
SPV client aka. Thin client is a bit different from normal Bitcoin Core. They do not download and synchronize with the blockchain on your computer. Your private keys are generated on your own computer and it isn't shared with the server. The server just allows your client to request information and broadcast your transaction. Electrum is open sourced so you can verify and compile the code yourself. The security risk isn't huge unless you have malware on your computer. The best method of securing the wallet is to generate a paper wallet offline and send your funds there.
Having 10 connections means that the client have 8 outgoing connection and 2 incoming connection. It doesn't help you to sync since 2 incoming connection means others are connecting to you to get blocks. The main factors are CPU verification speed, disk IO speed and peer's speed.
You can also try to download the blockchain by torrent to sync faster.