hello
i have visual dolphin ( ERP software and POS ) connected to a SQL server 2005 .
I have about 30 users working in the same time but the program is extremely slow ( database is about 2.5 GB )
i thought it was my network in the first place , so i changed everything to giga connection , removed as much nodes as possible , I even stopped my ASA firewall but the issue remained .

i thought it is an issue with my server maybe a cpu or memory bottleneck but i am not sure :
Poweredge 2900
Intel Xeon CPU E5310 @1.60 GHz ( 4 CPUs)
Memory 4094 MB RAM
OS : window server 2003

I was wondering if i should run a maintenance plan . I know nothing about databases .
what can cause this issue?
It might be your server if you have other services loaded on it as well. Looking at the specs, this is an entry level server. Check server performance logs and observe the amount of memory used and cpu load. Also this might be an IO problem. Databases exchange very little information per transaction, but have a lot of transaction requests. If you cannot provide the necessary IO speed, you will notice some performance degradation in database reads/writes. Either configure the server hard drives to be RAID 0+1 (you need minimum 4 hard drives) or go pro with IO king; SAN storage.

Can you list what services are running on the server? (AD? DNS? DHCP? Mail? RRAS? Web? .....)
Mr class my HDD are 0+1 raid ( 4 hdd about 500 GB in total - usable ) I also have a 16 TB black-armor 400
i shrinked my database , re-indexed and reorganized it .
even though the window server 2003 is showing as 32bit (x86 ) i will add another FBD memory stick ( 2 or 4 GB perhaps ) i am confident now it is an issue with my server ..took about 20 min just t shut down

even though is it server 2003 standard R2 edition yet i can see it has PAE ( physical address extension ) so it should hold up to 64 GB maximum
It is actually normal for a server to take this much time to shutdown. Don't forget this is a server that is running multiple services, so it needs time to stop every service and produce a log about it. If your Windows Server is 32bit, then it won't use more than 3.33GB no matter how much more ram you have installed.
as for microsoft , PAE should give 32 bit OS up t 64 GB ..but i am not sure if server 2003 standard uses this technique .