Businesses have been warned that "closing doors and windows" in cyberspace is as important as in their actual offices, in the fight against crime.
The Lovebug virus struck millions of PCs worldwide
Police, companies and experts looked at ways of tackling the growing problem of internet crime at a conference.
Experts believe virus and trojan attacks, spam email and hacking cost Welsh firms millions of pounds a year.
Around 200 delegates discussed an action plan in Llangollen on Wednesday.
It was drawn up at a first conference, held in Cardiff a year ago.
Joining representatives from all four Welsh police forces were the national hi-tech crime unit, Microsoft and the Welsh Development Agency.
Businesses are being urged to review their security procedures.
The importance of effective 'firewalls', password policy and virus checking were also highlighted.
Companies are being advised to make sure they keep regular back-ups of data critical for their business.
One company taking part in the conference was cheese-maker South Caernarfon Creameries which has already faced disruption from malicious 'worm' code.
The dairy's computer system became infected by a virus which turned a server into a 'zombie' that sent out thousands of spam emails.
The firm was left off-line for two days after its internet provider shut the system down.
BOOSTING CYBER SECURITY
Use anti-spyware and anti-virus programs
Make sure updates to your operating system are installed
Use an Internet firewall and make sure it is switched on
Use complex passwords and change them often
Protect the physical security of hardware
Keep secure back-ups of important data
Senior police officers say the threat from such attacks is very real.
"High-tech crime, as with all reports of crime, is taken extremely seriously," said Detective Superintendent Chris Corcoran of North Wales Police.
"However, when it comes to crime prevention, everyone can take active steps and measures to protect themselves from on-line criminals".
He added: "Learning to close doors and windows to prevent criminals entering is as pertinent to electronic security as it is to physical security".
It is hoped the one-day conference at the International Eisteddfod pavilion in Llangollen will help to share best practice between Welsh companies.