SBS 2008 SP2 - Slow performance - Backup failure - Admin issues - Network save time + access slow

Hello,

I have been having several issues within my company.  We are currently running SBS 2008 and I have encountered the following issues:

1. Slow start up - often 30 minutes (with roles, services, feature, redirected folders)
2. Programs often take 2-3 minute to open (SBS monitor, Exchange server, and various windows)
3. SQL server uses a lot of resources even though it's been restricted on memory (3 GB mem)
4. On client machines save time often takes a while
5. VPN often fails to verify and employees will have random disconnects.
6. Inability to maintain a stable VPN connection
7. Client machines will be slow to log onto the network
8. Slow network at times (100 Mbit network switch)
9. Client saves are slow
10. Administrator related issues (file access)

User information:

• Supported users: 15-18
• Est. email per day: 200 sent 
• Est. 300-350 recieved

There is a recommended system spec however it is a lot lower than our server.

System Spec:

• ASUS - P7P55D-E (http://www.asus.com/Motherboards/Intel_Socket_1156/P7P55DE/)
• 16 GB RAM (1600MHz | 9-9-9-24) 4 x 4GB
• 2x 2TB - 5400 RPM - SATA (http://www.storagereview.com/samsung_spinpoint_f4eg_review_hd204ui)
• I5 760 Processor (2.80 GHz)
• ATI graphics card

The machines is approx. 1 year old. No RAID config.

Apps:

1. SBS
2. Exchange
3. SQL
4. Acronis

Motherboard usage:

• Everything is directly processed via the MB
• NO - seperate RAID controllers, network cards etc.

Last updates installed:

• 20/01/2012
• # of updates available to install est. 85 (unable to check due to error currently - will update when it works)

Reducing / stopping services such as SQL and WSUS (not currently used) have increased the speed slightly. Initially after upgrading the memory to 16GB (from 8GB) the server slowed completely down. In addition, the server was working fine approx. 5 months ago then slowly it's been getting worst. Changes include the above RAM and about 7 new employees.

Errors:

The Kerberos client received a KRB_AP_ERR_MODIFIED error from the server box-04$. The target name used was RPCSS/LAP11.*.local. This indicates that the target server failed to decrypt the ticket provided by the client. This can occur when the target server principal name (SPN) is registered on an account other than the account the target service is using. Please ensure that the target SPN is registered on, and only registered on, the account used by the server. This error can also happen when the target service is using a different password for the target service account than what the Kerberos Key Distribution Center (KDC) has for the target service account. Please ensure that the service on the server and the KDC are both updated to use the current password. If the server name is not fully qualified, and the target domain (*.LOCAL) is different from the client domain (*.LOCAL), check if there are identically named server accounts in these two domains, or use the fully-qualified name to identify the server.

AND

DCOM was unable to communicate with the computer asset-remote.*.local using any of the configured protocols.

Additional info:

The implementation was before my time so i haven't had any direct input on setup / spec.  Admittedly I am quite inexperienced in this area however, am willing to learn and would be extremely grateful for any help offered.

In addition, any backup software recommendations would be great i.e. Acronis / Symantec.

I will update this post as I think of any additional issues and/or fixes for them.

Thank you !!